CHSiCl

CHSiCl is a simple organosilicon chloride with the empirical formula C1H1Si1Cl1. It is a colorless, volatile liquid that is typically obtained as a gas or as a low-boiling liquid under moderate pressure. The molecule consists of a silicon atom bonded to one carbon atom, two hydrogen atoms, and a chlorine atom, giving silicon a formal oxidation state of +1 and forming a partially polarized Si–Cl bond that is highly reactive toward nucleophiles.

The most common synthetic route involves the chlorination of methylsilane (CH3SiH3) using chlorine gas in the presence of a Lewis acid catalyst such as AlCl3. The reaction proceeds through a radical mechanism with the loss of HCl and yields CHSiCl as the major product alongside higher chlorinated species (CH2SiCl2 and CH3SiCl3) that must be removed by fractional distillation. Alternate preparation uses the direct reaction of silane with chloromethyl reagents under controlled conditions to suppress overchlorination.

CHSiCl serves primarily as an intermediate in organosilicon chemistry. It is used in the synthesis of silicone polymers, where it reacts with vinyl groups to introduce silicon–chlorine functionalities that can later be polymerized or cross‑linked. It also functions as a chlorosilane building block for protecting groups and as a source of SiCl in the synthesis of organometallic silicacyclobutanes.

From a safety perspective, CHSiCl is highly reactive with moisture, liberating corrosive HCl and heat. It can form flammable vapors, and its vapors are irritating to the eyes, throat, and skin. Safe handling requires inert atmosphere techniques, proper ventilation, and use of personal protective equipment. Adequate fire‑suppression measures, such as dry powder extinguishers, should be available in laboratories that handle this compound.

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